<?php
/**
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 *
 * @category   Zend
 * @package    Zend_Db
 * @subpackage Adapter
 * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 * @version    $Id: Sqlite.php 18951 2009-11-12 16:26:19Z alexander $
 */


/**
 * @see Zend_Db_Adapter_Pdo_Abstract
 */
require_once 'Zend/Db/Adapter/Pdo/Abstract.php';


/**
 * Class for connecting to SQLite2 and SQLite3 databases and performing common operations.
 *
 * @category   Zend
 * @package    Zend_Db
 * @subpackage Adapter
 * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */
class Zend_Db_Adapter_Pdo_Sqlite extends Zend_Db_Adapter_Pdo_Abstract
{

	/**
	 * PDO type
	 *
	 * @var string
	 */
	protected $_pdoType = 'sqlite';

	/**
	 * Keys are UPPERCASE SQL datatypes or the constants
	 * Zend_Db::INT_TYPE, Zend_Db::BIGINT_TYPE, or Zend_Db::FLOAT_TYPE.
	 *
	 * Values are:
	 * 0 = 32-bit integer
	 * 1 = 64-bit integer
	 * 2 = float or decimal
	 *
	 * @var array Associative array of datatypes to values 0, 1, or 2.
	 */
	protected $_numericDataTypes = array(
	Zend_Db::INT_TYPE    => Zend_Db::INT_TYPE,
	Zend_Db::BIGINT_TYPE => Zend_Db::BIGINT_TYPE,
	Zend_Db::FLOAT_TYPE  => Zend_Db::FLOAT_TYPE,
        'INTEGER'            => Zend_Db::BIGINT_TYPE,
        'REAL'               => Zend_Db::FLOAT_TYPE
	);

	/**
	 * Constructor.
	 *
	 * $config is an array of key/value pairs containing configuration
	 * options.  Note that the SQLite options are different than most of
	 * the other PDO adapters in that no username or password are needed.
	 * Also, an extra config key "sqlite2" specifies compatibility mode.
	 *
	 * dbname    => (string) The name of the database to user (required,
	 *                       use :memory: for memory-based database)
	 *
	 * sqlite2   => (boolean) PDO_SQLITE defaults to SQLite 3.  For compatibility
	 *                        with an older SQLite 2 database, set this to TRUE.
	 *
	 * @param array $config An array of configuration keys.
	 */
	public function __construct(array $config = array())
	{
		if (isset($config['sqlite2']) && $config['sqlite2']) {
			$this->_pdoType = 'sqlite2';
		}

		// SQLite uses no username/password.  Stub to satisfy parent::_connect()
		$this->_config['username'] = null;
		$this->_config['password'] = null;

		return parent::__construct($config);
	}

	/**
	 * Check for config options that are mandatory.
	 * Throw exceptions if any are missing.
	 *
	 * @param array $config
	 * @throws Zend_Db_Adapter_Exception
	 */
	protected function _checkRequiredOptions(array $config)
	{
		// we need at least a dbname
		if (! array_key_exists('dbname', $config)) {
			/** @see Zend_Db_Adapter_Exception */
			require_once 'Zend/Db/Adapter/Exception.php';
			throw new Zend_Db_Adapter_Exception("Configuration array must have a key for 'dbname' that names the database instance");
		}
	}

	/**
	 * DSN builder
	 */
	protected function _dsn()
	{
		return $this->_pdoType .':'. $this->_config['dbname'];
	}

	/**
	 * Special configuration for SQLite behavior: make sure that result sets
	 * contain keys like 'column' instead of 'table.column'.
	 *
	 * @throws Zend_Db_Adapter_Exception
	 */
	protected function _connect()
	{
		/**
		 * if we already have a PDO object, no need to re-connect.
		 */
		if ($this->_connection) {
			return;
		}

		parent::_connect();

		$retval = $this->_connection->exec('PRAGMA full_column_names=0');
		if ($retval === false) {
			$error = $this->_connection->errorInfo();
			/** @see Zend_Db_Adapter_Exception */
			require_once 'Zend/Db/Adapter/Exception.php';
			throw new Zend_Db_Adapter_Exception($error[2]);
		}

		$retval = $this->_connection->exec('PRAGMA short_column_names=1');
		if ($retval === false) {
			$error = $this->_connection->errorInfo();
			/** @see Zend_Db_Adapter_Exception */
			require_once 'Zend/Db/Adapter/Exception.php';
			throw new Zend_Db_Adapter_Exception($error[2]);
		}
	}

	/**
	 * Returns a list of the tables in the database.
	 *
	 * @return array
	 */
	public function listTables()
	{
		$sql = "SELECT name FROM sqlite_master WHERE type='table' "
		. "UNION ALL SELECT name FROM sqlite_temp_master "
		. "WHERE type='table' ORDER BY name";

		return $this->fetchCol($sql);
	}

	/**
	 * Returns the column descriptions for a table.
	 *
	 * The return value is an associative array keyed by the column name,
	 * as returned by the RDBMS.
	 *
	 * The value of each array element is an associative array
	 * with the following keys:
	 *
	 * SCHEMA_NAME      => string; name of database or schema
	 * TABLE_NAME       => string;
	 * COLUMN_NAME      => string; column name
	 * COLUMN_POSITION  => number; ordinal position of column in table
	 * DATA_TYPE        => string; SQL datatype name of column
	 * DEFAULT          => string; default expression of column, null if none
	 * NULLABLE         => boolean; true if column can have nulls
	 * LENGTH           => number; length of CHAR/VARCHAR
	 * SCALE            => number; scale of NUMERIC/DECIMAL
	 * PRECISION        => number; precision of NUMERIC/DECIMAL
	 * UNSIGNED         => boolean; unsigned property of an integer type
	 * PRIMARY          => boolean; true if column is part of the primary key
	 * PRIMARY_POSITION => integer; position of column in primary key
	 * IDENTITY         => integer; true if column is auto-generated with unique values
	 *
	 * @param string $tableName
	 * @param string $schemaName OPTIONAL
	 * @return array
	 */
	public function describeTable($tableName, $schemaName = null)
	{
		$sql = 'PRAGMA ';

		if ($schemaName) {
			$sql .= $this->quoteIdentifier($schemaName) . '.';
		}

		$sql .= 'table_info('.$this->quoteIdentifier($tableName).')';

		$stmt = $this->query($sql);

		/**
		 * Use FETCH_NUM so we are not dependent on the CASE attribute of the PDO connection
		 */
		$result = $stmt->fetchAll(Zend_Db::FETCH_NUM);

		$cid        = 0;
		$name       = 1;
		$type       = 2;
		$notnull    = 3;
		$dflt_value = 4;
		$pk         = 5;

		$desc = array();

		$p = 1;
		foreach ($result as $key => $row) {
			list($length, $scale, $precision, $primary, $primaryPosition, $identity) =
			array(null, null, null, false, null, false);
			if (preg_match('/^((?:var)?char)\((\d+)\)/i', $row[$type], $matches)) {
				$row[$type] = $matches[1];
				$length = $matches[2];
			} else if (preg_match('/^decimal\((\d+),(\d+)\)/i', $row[$type], $matches)) {
				$row[$type] = 'DECIMAL';
				$precision = $matches[1];
				$scale = $matches[2];
			}
			if ((bool) $row[$pk]) {
				$primary = true;
				$primaryPosition = $p;
				/**
				 * SQLite INTEGER primary key is always auto-increment.
				 */
				$identity = (bool) ($row[$type] == 'INTEGER');
				++$p;
			}
			$desc[$this->foldCase($row[$name])] = array(
                'SCHEMA_NAME'      => $this->foldCase($schemaName),
                'TABLE_NAME'       => $this->foldCase($tableName),
                'COLUMN_NAME'      => $this->foldCase($row[$name]),
                'COLUMN_POSITION'  => $row[$cid]+1,
                'DATA_TYPE'        => $row[$type],
                'DEFAULT'          => $row[$dflt_value],
                'NULLABLE'         => ! (bool) $row[$notnull],
                'LENGTH'           => $length,
                'SCALE'            => $scale,
                'PRECISION'        => $precision,
                'UNSIGNED'         => null, // Sqlite3 does not support unsigned data
                'PRIMARY'          => $primary,
                'PRIMARY_POSITION' => $primaryPosition,
                'IDENTITY'         => $identity
			);
		}
		return $desc;
	}

	/**
	 * Adds an adapter-specific LIMIT clause to the SELECT statement.
	 *
	 * @param string $sql
	 * @param integer $count
	 * @param integer $offset OPTIONAL
	 * @return string
	 */
	public function limit($sql, $count, $offset = 0)
	{
		$count = intval($count);
		if ($count <= 0) {
			/** @see Zend_Db_Adapter_Exception */
			require_once 'Zend/Db/Adapter/Exception.php';
			throw new Zend_Db_Adapter_Exception("LIMIT argument count=$count is not valid");
		}

		$offset = intval($offset);
		if ($offset < 0) {
			/** @see Zend_Db_Adapter_Exception */
			require_once 'Zend/Db/Adapter/Exception.php';
			throw new Zend_Db_Adapter_Exception("LIMIT argument offset=$offset is not valid");
		}

		$sql .= " LIMIT $count";
		if ($offset > 0) {
			$sql .= " OFFSET $offset";
		}

		return $sql;
	}

}
